Buckles – buttons – clasps – etc. – Including readily dissociable fastener having numerous,... – Having mounting surface and filaments constructed from...
Reexamination Certificate
1999-01-21
2001-04-03
Sakran, Victor N. (Department: 3626)
Buckles, buttons, clasps, etc.
Including readily dissociable fastener having numerous,...
Having mounting surface and filaments constructed from...
C024S442000, C024S447000, C024S450000
Reexamination Certificate
active
06209177
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a molded surface fastener made of thermoplastic synthetic resin material and having engaging elements molded integrally with a surface of a flat substrate and independently of each other, and specifically, to a molded surface fastener which can be molded in various sizes, ranging from a fine size to a normal size, which is suitable for various usage in many fields, and which can be molded continuously and efficiently through a single step by using a simple apparatus. This invention also relates to a molding method and a molding apparatus of the same molded surface fastener.
2. Description of the Related Art
Conventional molded surface fastener is produced by various methods. A typical example is a method for producing a surface fastener by complete batch process by injection molding. Another typical method is a process for molding engaging elements successively and integrally with a flat substrate by rotating in one direction a die wheel having on its peripheral face a large number of cavities for molding the engaging elements and continuously introducing molten resin material into the peripheral face of the die wheel. By these methods, various conventionally and widely known shapes of engaging elements such as a palm shape and a hook shape can be molded.
Furthermore, another know method employs an extrusion die in which a large number of substantially T-shaped extruding openings are arranged side by side and have lower ends communicating with each other. By extruding molten resin simultaneously through the extruding openings, a plurality of ribs which are substantially T-shaped in section are successively molded on a surface of a flat substrate. Then, the molten resin molded material is hardened by cooling. Thereafter, the ribs are successively cut in a perpendicular direction or in a direction with an appropriate inclination angle with respect to a horizontal plane where the ribs are arranged such that each of the cut ribs have a predetermined thickness. At this time, the flat substrate is left uncut. After the cutting process, the flat substrate is drawn in a direction of molding, until the cut engaging elements are separated from each other with a desired pitch, thereby producing the molded surface fastener.
According to the above molding methods, the shape or the size of the engaging elements is limited, if their productivity is high, while a continuous molding is difficult to achieve or a number of processes increases so that the productivity is decreased, if the shape or the size of the engaging elements is optional to some extent. Both the cases have extreme advantages and disadvantages.
Particularly, in the above process wherein the ribs of the molten resin molded material having ribs extruded from the extrusion die to the surface of the flat substrate are cut and the substrate is drawn, a sectional shape of an engaging head of each engaging element can be optical to some extent. However, three steps, i.e., an extrusion molding, cutting of ribs, and drawing are required. Specifically, a high processing accuracy is required especially to cut the ribs, so that maintenance and management for this purpose requires considerable workload and time.
SUMMARY OF THE INVENTION
The present invention has been accomplished to solve the above problems, and specifically, it is an object of the invention to provide a molded surface fastener which can be continuously molded by an entirely new molding mechanism and which has engaging elements molded to have new shapes which are not conventional and of various sizes so that maintenance and management can be easy to achieve and a productivity is high. It is also an object of the invention to provide a molding process and a molding apparatus of the molded surface fastener.
The above object is achieved by the invention stated below.
According to a first aspect of the present invention, there is provided a molded surface fastener comprising a flat substrate and a large number of engaging elements integrally molded with substrate, wherein each of the engaging elements has a stem standing on a surface of the flat substrate and an engaging head projecting from an end of the stem toward at least one side thereof, a thickness of each of the engaging elements in a direction perpendicular to a projecting direction of the engaging head gradually increasing from a top of the engaging head to a base end of the stem.
With the molded surface fastener of the present invention having the above shape, the engaging elements do not easily fall due to a force (shearing force) in a direction parallel to the surface of the flat substrate or an urging force from above in a oblique direction with respect to the substrate. Also, when the loops which are companion engaging elements are pulled obliquely upward in an engaged state with the stems, the loops are necessarily guided to boundary areas between the stems and the engaging heads, thereby preventing rising of the engaging heads in the loops and preventing the loops from being easily detached from the stems. On the other hand, because a thickness of each engaging head in a direction perpendicular to the projecting direction thereof is formed to gradually increase from its top portion to its end portion, the engaging elements can easily enter a group of the opposed loops, and further each engaging element can spread each loop sideways at the time of entering. Therefore, although the width of the engaging head gradually increases toward its projecting end, the engaging head can be easily inserted into the loop. Further, the engaged companion loop is not easily detached due to a gouged shape of a neck portion of the engaging element which is a boundary between the engaging head and the stem thereof, as compared with the conventional molded surface fastener wherein the width of the engaging head is constant in the direction, thereby increasing an engaging rate, an engaging force, and a peeling force.
According to the present invention, the engaging head may project in a direction perpendicular to a molding direction of the molded surface fastener. Because the surface fastener of this shape can be continuously molded by a manufacturing process and a manufacturing apparatus, which will be described later, without producing a specially shaped molding die for engaging elements with a special shape. Therefore, a productivity is remarkably increased.
According to the present invention, it is preferable that the flat substrate has recessed grooves which extend continuously in a direction perpendicular to a projecting direction of the engaging head between the engaging elements which are adjacent to each other in the projecting direction of the engaging head.
Alternatively, the flat substrate has recessed grooves which extend continuously in a projecting direction of the engaging head between the engaging elements which are adjacent to each other in a direction perpendicular to the projecting direction of the engaging head.
The above two types of the recessed grooves may be formed to be perpendicular to each other.
By forming the recessed grooves in the surface of the substrate, an apparent thickness of the flat substrate can be decreased so that flexibility of the surface fastener can be increased and generation of a crack in the substrate between the adjacent engaging elements can be prevented. Furthermore, because side wall faces of the recessed grooves can function as guide faces for guiding the companion loops to the rising base portion of the engaging elements, the engaging rate of the engaging elements with the companion loops can be increased.
According to the present invention, an end of the engaging head faces a surface of the flat substrate. With this shape, in addition to the above-described functions and effects, even if the engaged companion loops are pulled upward, the loops are not easily detached from the engaging heads, thereby further increasing the engaging force as compared with a case where the engaging heads linea
Finnegan Henderson Farabow Garrett & Dunner LLP
Sakran Victor N.
YKK Corporation
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